If you decide to upgrade your current subscription plan, this change
will be effective immediately. You don't have to wait for your current subscription
period to end in order to change your plan. This rule applies to both monthly
and annual plans. Upgrading your plan at any point will initiate a prorated upgrade —
you will be charged based on the number of days remaining before your subscription renewal,
and you'll receive a refund for the unused portion of your original plan.